Cam grinding apparatus



July 24, 1951 c. J. GREEN cAM @BINDING APPARATUS 4 Sheets-Sheet 1 FiledDec. 17, 1948 July 24,1951 c. J. GREEN 2,561,981

CAM GRINDING APPARATUS Filed Dec. 17, 1948 4 Sheets-$11661. 2

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. I nuevztor CLA/ENCE IG/eem gm w. ttorney July 24, 1951 c. J. GREEN2,561,981

CAM GRINDING APPARATUS Filed Dec. 17, 1948 l 4 'sheets-sheet s u Inuentor' F g 10 CLARENCE LIS/25m .Bgm b5. edd".

Httorneg C. J. GREEN A GRINDING APPARATUS July 24, 1951 4 Sheets-Sheet 4Filed Dec. 17, 1948 Patented July 24, 1951 CAM GRINDING APPARATUSClarence J. Green, Worcester, Mass., assignor to Norton Company,Worcester, Mass., a corporation of Massachusetts Application December17, 1948, Serial No. 65,921

8 Claims. (Cl. 51-101) The invention relates to grinding machines andmore particularly to a cam grinding machine.

One object of the invention is to provide a simple and thoroughlypractical cam grinding machine for grinding predetermined contours on a.work piece. Another object is to provide a cam grinding apparatus forgrinding a contour of a predetermined length on the periphery of a workpiece. Another object is to provide a. cam grinding apparatus forgrinding a contour of a prel determined length around the periphery of aroll, regardless of the diameter of the roll, from the same master cam.Another object is to provide a cam grinding apparatus with an adjustablespeed-up device for speeding up rotation of the work piece being groundrelative to rotation of the master cam. Another object is to provide acam grinding apparatus having a single master cam with a directproportional device to speed up the rotation of the roll being ground`relative to the rotation of the master cam so that the original shapecan be extended around the periphery of the roll as it is reduced insize by regrinding operations so as to produce the same shape in blanksbeing rolled.

Another object of the invention is to provide a cam grinding apparatusfor grinding a predetermined shape in the periphery of a roll used in arolling operation. Another object is to provide an apparatus forgrinding the periphery of rolls with an adjustable work rotationspeed-up mechanism for` speeding up rotation of the roll being gyiundrelative to the master cam whereby `a single naster cam serves to grinda form of the same peripheral length regardless of the diameter of theroll being ground. A further object is to provide a cam grindingapparatus for grinding a form of a predetermined length on the peripheryof a roll being ground by means of a single master cam as the roll isreduced in diameter due to successive regrinding operations so that luniformly shaped blanks may be rolled there- In the accompanyingdrawings, in which is shown one of various possible embodiments of themechanical features of this invention,

Fig. 1 is a fragmentary plan view of the improved cam grinding apparatushaving parts broken away and shown in section to show part of the workdriving mechanism;

Fig. 2 is a fragmentary front elevation of the work driving mechanismshowing the two-speed clutch, taken approximately on the line 2-2 ofFig. 1;

Fig. 3 is a right hand end elevation, taken ap- 2 proximately on theline 3-3 of Fig. 1, showing a portion of the work driving mechanism;

Fig. 4 is a fragmentary cross section, on an enlarged scaleI takenapproximately on the line 4 4 oi Fig. 1, through the rock bar showing aright hand elevation of the work speed-up and slow-down mechanism;

Fig. 5 is a fragmentary vertical sectional view, taken approximately onthe line 5-5 of Fig. 4;

Fig. 6 is a fragmentary vertical sectional view, taken aproximately onthe line 5-5 of Fig. 4, showing the work speed-up mechanism inelevation;

Fig. 7 is a fragmentary cross sectional view, on an enlarged scale,taken approximately on the line 4-4 of Fig. 1, similar to Fig. 4 butshowing the parts in another position;

Fig. 8 is a diagrammatic view of a metal rolling apparatus in which thelower roll is ground on the improved cam grinding machine;

Fig. 9 is a view of the lower roll showing the extended formed surfaceon the roll when the roll has been reground to a smaller diameter;

Fig. 10 is a side elevation of an article rolled 5 by the apparatusshown in Fig. 8; and

Fig. 11 is a front elevation of the grinding machine. Y

A cam grinding apparatus has been illustrated in the drawings comprisinga base 9 which supports a longitudinally movable table ||l on the usualV and flat way (not shown) on the base of the machine. A transverselymovable rotatable grinding wheel is provided which is mounted in aconventional manner on a transversely movable wheel slide 30 so that thewheel may be moved toward and from the work table I0 to ygrind a workpiece to the required and predetermined sizeA A manually operable feedwheel 3| is mounted on the front of the machine base and is operativelyconnected to rotate a feed screw (not shown) to cause the grinding wheeland the wheel slide 30 to move transversely toward and from the worktable I0, depending upon the direction of rotation of the feed wheel 3|.This mechanism is substantially identical with that disclosed in theprior U. S. patent to C. H. Norton No. 762,838 dated June 14, 1904, towhich reference may be had for details of disclosure not containedherein. The feed wheel 3| may be actuated either manually orautomatically as desired. A mechanically actuated feed pawl 32, such asshown in the prior patent above referred to, is reciprocatedautomatically to advance the grinding wheel at the ends of thereciprocatory stroke of the work table i0.

The work table I may be reciprocated longitudinally relative to the base9 by means of a manually operable traverse mechanism comprising atraverse wheel 200 rotatably mounted on the front of the machine base.The traverse wheel 200 is connected to rotate a gear 20I which mesheswith a gear 202 mounted on a rotatable shaft 203. The shaft 203 alsosupports a gear 204 which meshes with a rack bar 205 depending from theunderside of the work table 0. It will be readily apparent from theforegoing disclosure that a manual rotation of the traverse wheel 200will be imparted through the rack and gear mechanism above described toproduce a longitudinal traversing movement of the table I0. Thedirection of rotation of the traverse wheel 200 serves to determine thedirection of Ymovement of the table I0.

The table I0, if desired, may be reciprocated longitudinally by a poweroperated mechanism such as shown in the prior patent above referred to.This mechanism may comprise a rotatable power driven shaft 206 which isdriven by means of a multiple speed drive contained with a casing 201.The rotatable shaft 206 is connected through a reversing clutch (notshown) which is actuated by means of a reversing lever 208. Thereversing lever 208 is actuated by adjustable table dogs 209 and 2I0which are adjustably mounted in a T-slot 2II formed in the front edge ofthe table III. This table traverse mechanism above described issubstantially identical to that shown in the above mentioned priorpatent, to which reference may be had for details of disclosure notcontained herein. The table I0 serves as a support for a rock bar I2.The rock bar I2 is provided with trunnions I3 and I4 at its oppositeends (Fig. 1) which are rotatably journalled in brackets I5 and I6. Thebrackets I5 and I6 are flxedly mounted on the upper surface of the tableI0.

The rock bar I2 serves as a support for a headstock I1 and a footstockI8 which are provided with work supporting centers I9 and 20respectively. The headstock I1 is provided with a rotatably mountedmaster cam spindle 2I which is supported in bearings 22 and 23. A mastercam 24 is mounted on the master cam spindle 2|. A frame 25 is xedlymounted on the table I0 and serves as a support for a rotatably mountedmaster cam roller 26. The master cam roller 26 is keyed on a rotatableshaft 21 which is journalled in brackets 28 and 29 which are formedintegral with the frame 25.

A casing 35 is xedly mounted on the table I0 and serves as a support fora work driving motor 36. The work driving motor 36 is provided with amotor shaft 31 which is connected to rotate a worm 38. The worm 38meshes with a worm gear 39 which is keyed on a rotatable shaft 40. Theshaft 40 is journalled in antifriction bearings 4I and 42 which aresupported within the casing 35.

A two-speed drive is provided between the shaft 40 and the master camspindle 2I to facilitate changing the speed of rotation of the mastercam spindle 2I and the work piece being ground. This mechanism maycomprise a pair of gears 45 and 46 which are keyed on opposite ends ofthe shaft 4l. The gears 45 and 46 mesh with gears 41 and 48 respectivelywhich are keyed on rotatable clutch members 49 and 50 respectively. Theclutch members 49 and 50 are rotatably supported on a shaft 5I which isjournalled for rotation within bearing surfaces formed within the 4clutch members 49 and 50. A slidably mounted clutch member 52 (Fig. 2)is slidably keyed on the shaft 5I. A manually operable clutch shiftinglever 53 is fixedly supported on a rock shaft 54. The rock shaft 54 alsosupports a yoked member (not shown) which engages a groove (not shown)on the clutch member 52. It will be readily apparent from the foregoingdisclosure that by manual shifting of the lever 53, the

clutch member 52 may be engaged either with the clutch member 49 or theclutch member 50 to impart a rotary motion to the shaft 5I.

`A multiple V-groove pulley 55 is keyed on the left hand end of theshaft 5I. The pulley 55 is connected by multiple V-belts (not shown)with a multiple V-groove pulley 56 which is supported by ananti-friction bearing 51. A universal joint 58 is drivingly connectedwith the pulley 56. The universal joint 58 Ls lixedly connected to oneend of a shaft 59. A universal joint 60 connects the right hand end ofthe shaft 59 with the master cam spindle 2|. It will be readily apparentfrom the foregoing disclosure that by providing the universal joints 58and 60, a substantially uniform rotation may be imparted to the mastercam spindle 2l and the work piece being ground during oscillatingmovement of the rock bar I2.

In the rolling of shaped metallic blanks such as is used in thesilver-ware and cutlery trade, it is desirable to provide a roll for therolling operation having a predetermined form on its periphery so that awork blank being rolled will be produced having the desired longitudinalshape. In order to produce a predetermined shape in the periphery of theroll used in the rolling operation from a single master cam, it isdesirable to provide a suitable speed-up mechanism between the mastercam spindle and the work piece being driven thereby to facilitate anacceleration of the work speed relative to the speed of rotation of themaster cam 24 so that as the roll being ground is reduced in diameter bysuccessive regrinding operations, a form of a predetermined length maybe produced on the peripheral surface of the roll. This mechanismenables rolling work pieces to the same longitudinal shape regardless ofthe diameter of the roll being ground without the necessity of providinga plurality of master cams. The speed-up mechanism as illustrated in thedrawings is mounted on the right hand end of the master cam spindle 2I.

The master cam spindle 2I is provided with an integral flange 65 (Figs'.5 and 6) and a cylindrical portion 66. The cylindrical portion 66 of themaster cam spindle 2I serves as a support for an annular member 61. Aspacing collar 68 is interposed between the annular member 61 and theflange 65. A plurality of clamping screws 69 (only one of which is shownin Fig. 5) are provided for locking the annular member 61 and thespacing collar 68 to the flange 65 so that the annular member 61 isrotated with the master cam spindle 2|. A bracket 10 is mounted on theperiphery of the annular member 61. A pair of clamping screws 1I and 12pass through the bracket 10 and have their heads engaging an arcuateT-slot 13 formed in the periphery of the annular member 61. It will bereadily apparent from the foregoing disclosure that by loosening thescrews 1I and 12, the bracket 10 may be adjusted about the periphery ofthe member 61 as desired. The bracket 10 serves as a support for anarcuate member 14 which is pivotally connected by means of a stud 15with the bracket 18. The right hand end of the arcuate member (Fig.

. 5' 4) is provided with a roller 16 which is supported by a stud 11carried by the arcuate member 14. The roller 16 is arranged to engagethe internal cam 1-8 formed on the inner periphery of an annular ring19. The ring 19 is provided with a pair of downwardly extending lugs 80and 8| which are fastened to the rock bar I2 by means of cap screws 82and 83 so that the annular ring 19 is rigidly positioned on the rock barI2.

A slide 85 is supported by a radially extending slot 86 formed in theannular member 61.- The slide 85 carries a stud 81 which rides in anelongated arcuate slot 88 formed in the arcuate member 14. A pair ofplates 89 and 90 are flxedly mounted on the peripheral surface of theannular member 61 to prevent the slide 85 from moving outwardly beyondthe maximum position as illustrated in Fig. 4.

A driving head 94 is rotatably mounted on the cylindrical portion 66 ofthe master cam spindle 2| and is held in position thereon by means of acollar 95. The driving head 94 is provided with an angularly positionedslotl 96 which is preferably arranged at approximately 45 relative to aradial -plane passing through the axis of the master cam spindle. Theslide 85 is provided with a stud 98 which supports a roller 91. Theroller 91 rides in the slot 96. It will be readily apparent from theforegoing disclosure that when the slide 85 is moved downwardly (Fig. 4)in a radial direction relative to the annular member 61, the roller 91carried thereby riding in the angular slot 96 will impart anaccelerating motion to the driving head 94 so that the head 94 moves ata faster rate than the rotation of the annular member 61.

A tension spring 99 is provided for exerting a pull on the driving head94 in a clockwise direction relative to the annular member 61. The lefthand end of the spring is fastened to a stud carried by the annularmember 61. The right hand end of the spring is fastened to a stud |0|carried by the driving head 94. An adjustably mounted stop screw |85 issupported by a lug |06 on the annular member 61. A lock nut |01 servesto lock the screw |05 in adjusted position. It will be readily apparentfrom the foregoing disclosure that the tension of the spring 99 willserve normally to maintain a stop surface |08 on the driving head 94 inengagement with the stop screw |05.

A driving block ||0 is adjustably supported by means of a clamping boltI I on the driving head 94. The head of the clamping bolt III rides inan arcuate T-slot formed in the front face of the driving head 94.

A driving dog (not shown) is mounted on the neck I|3 of the roll ||4 tobe ground. The driving dog is arranged to engage an aperture ||6 in theface of the driving block I0.

The cam grinding apparatus disclosed is particularly intended forgrinding a peripherally extending form on a roll utilized for a rollingoperation for rolling metallic blanks -such as spoon blanks formanufacturing silver spoons and the like in which a blank must be formedof varying thickness and shape from length to length. To illustrate, arolling apparatus has been illustrated in Fig. 8 comprising the shapedroll I I4 which is located in a vertical plane with a cylindrical rollII5. A metal blank I|6 to be rolled is provided at its right hand endwith an enlarged end portion ||8v which is arranged to be engaged by alongitudinally extending `groove I I1 formed in the periphery of theroll I4. The roll I I4 is provided with a predetermined shaped portionrepresented by the arc A-B-C which when rotated in a clockwise directionwill roll the blank I I6 to produce a shaped blank |20 (Fig. 10).

As one example, the roll |I4 is preferably 51/2" in diameter and thefinished blank to be rolled is approximately 9". in length which meansthat the form produced on the roll ||4 `represented by the arc A-B-Cequals approximately 187.5". The master cam 24 is preferably designed sothat it will generate the predetermined shape on a 51/2" diameter roll.When the roll I|4 becomes worn during usage itis necessary to regrindthe periphery thereof to provide the desired shape.

and finish for the rolling operation. As the roll ||4 is reduced indiameter dueto successive regrinding operations, it is necessary toextend the formed surface represented by the arc A-B-C so that a 9"blank may be rolled thereby. For example when the roll ||4 becomes worndue to usage and successive regrinding operations from 51/2" in diameterto 5" in diameter, it will be necessary to increase the formed surfacethereon as represented byl the arc A-B---C to approximately 206.3 inorder to produce a formed blank 9" in length (Fig. 9).

After the groove ||1 becomes ground away, it may be necessary in aseparate grinding operation to regrind the longitudinal groove ||1 sothat it will grip 4the end ||8 of the blank II6 to be ground.

During the initial grinding operation on a 51/2" diameter roll, the stopscrew |05 is adjusted to turn the driving head 94 in a counterclockwisedi rection relative to the annular member 61 so that the'angular slot 96causes a downward movement of the roller 91 (Fig. 4) to move the slide8,5 also in a downward direction so as to rock the member 14 in aclockwise direction to position thefrollerv 16 so that it will notengage the cam face 18 during its rotary motion. The initial roll havingthe groove II1 previously formed therein may be ground in the usualmanner by feeding the grinding wheel II transversely into the surfacebfthe roll I|4 while the master cam spindle 2| rotated. The rock bar I2 isoscillated in a controlled movement by means of the master cam 24 togenerate the predetermined contour on the rll II4. This operation incase of a 9 blank as illustrated will produce a form A-BC. The remainingsurface of the roller as represented by the arc A-D-C being formed as atrue cylindrical surface. The roll ||4 thus produced is mounted in therolling machine and workpieces are inserted as the roll revolves so thatthe thickened end portion II8 is engaged by the groove |I1 which servesto pull the blank through the machine and due to the shape generated onthe surface as represented by the arc A-B-C, to generate a formed blank|28 as illustrated in Fig. 10.

When the initial roll becomes worn and requires regrinding, theregrinding reduces the diameter of the roll and it is necessary toextend the formed surface A-B--C through a greater angle in order toproduce a blank of the same length and shape. This is accomplished byrotating the master cam spindle 2| so that the roller 16 coincides withthe 187.5 position on the graduated scale formed on the side face of thering 19. With the roller 16 in this position, the screw |05 is adjustedso that the tension of the spring 99 will shift the driving head 94 in aclockwise direction relative to the annular member v61 so as to allowthe slide 85 to move upwardly (Fig. 4) a suicient distance so that themember 14 is rocked in a counterclockwise direction until the roller 16engages the surface of the cam 18. On the next regrinding operation itwill be necessary to lengthen the arc of grinding A--B-C and toaccomplish this, the bracket may be shifted around the periphery of theannular member 61 by loosening the clamping bolts 1| and 12 so that whenthe master cam spindle 2| is rotated, the roller 1B riding on thegradually rising surface of the cam 18 from the 187.5 position to zerowill transmit an accelerated motion to the driving head 94 to gain theadditional arc required so that the peripheral length of the surfacerepresented by the arc A-B-C (Fig. 8) will remain constant. In actualpractice the member 14 may be calibrated with a graduated scale so thatif a two degree gain is required, the bracket 10 may be preciselypositioned by consulting a calibrated table to give the desired results.

After the bracket 10 has been adjusted to its new position, the grindingoperation may then be started. As the roller 16 rides around the surfaceof the cam 18 in a counterclockwise direction, the rise of the cam 18acting through the roller 16 serves to rock the member 14 about itspivot stud in a clockwise direction to cause a downward movement of theslide 85. The downward movement of the slide 85 serves through theroller 91 riding in the angularly positioned slot 96 to accelerate therotary motion transmitted to the driving head 94. It will be readilyapparent from the foregoing disclosure that by adjustment of the bracket10 relative to the annular member 61, the desired amount of gain may behad in the acceleration of the driving head 94 to produce the desiredsurface on the roll ||4.

This adjustment is required on successive regrinding operations so thatfor example when the roll has been worn by use and regrinding t0 5" indiameter, it will require approximately 206.3 of arc A-B-C (Fig. 9) toproduce the desired length and contour on the finished blank |20. Whenthe roll becomes worn to the 5" diameter the roller |16 engages the cam18 at the l87.5 position and during its rotation from this position tozero, the roller 16 through the rocking of the member 14 causes adownward movement of the slide 85 to move the roller 91 downwardly inthe angularly positioned slot 96 so that the driving head 94 isaccelerated to move through 206.3 thereby producing a surface 0n theroll as represented in Fig. 9 that will produce a rolled blank |20 ofthe same length and contour. It will be readily apparent from theforegoing disclosure that by setting up the roller 16 for the initialangular rotation required and then by adjusting the position of thebracket 18 to vary the angular acceleration of the driving head 94 anydesired movement may be obtained to equalize and offset reductions indiameter of the roll being ground.

As illustrated in the drawings, the cam face 18 has been graduated to240 which is suflicicnt for certain classes of rolls to be ground. Theremaining ungraduated portion is a substantially cylindrical clearanceface joined with a blending curve which blends with the cam shape at thezero point. If desired the cam face 18 may be extended through a greaterarc if the nature of the work to be ground requires.

The operation of this improved grinding apparatus will be readilyapparent from the foregoing disclosure. Assuming adjustments have beenpreviously made so that the roller 16 remains out of contact with thecam 18, the initial full diameter roller H4 may be ground by the usualcam grinding operation, that is, by rotation of the master cam spindlewhich transmits the motion of the master cam 24 to cause a predeterminedrocking movement of the rock bar l2 to generate the predetermined shapeas represented by the arc A-B-C (Fig. 8) on the roll I4. After the rollbecomes worn and it becomes necessary to regrind the surface thereof themechanism is adjusted in a manner above described that is in the presentcase rotating the master cam spindle 2| until the roller 16 is oppositethe 187.5 position after which the stop screw |05 is adjusted intoengagement with the stop surface |88. The bracket 10 is then adjusted toshift the arcuate member 14 so as to vary the lever arms between theaxis of the stud 15, the axis of the stud 81 and the axis of the stud 11so that during the rotation of the master camshaft 2| and the annularmember 11 through l87.5, the driving head 94 will be accelerated thedesired amount so that the form generated on the roller |I4 asrepresented by the arc A-BC will be equal in length to the initial arc.On each successive regrinding operation it will be necessary to makeadjustment of the position of the bracket 10 to compensate for reductionin diameter of the roller being reground to insure generating a form ofthe predetermined peripheeral length.

As disclosed above, the mechanism has been described as set up forproducing a formed blank |23 which is 9" in length. If it is desired toproduce blanks of a different length, the mechanism is set upaccordingly to generate the desired arc A-B-C so that when used in therolling operation it will produce a blank of the desired length andcontour.

It will thus be seen that there has been provided by this inventionapparatus in which the various objects hereinabove set forth togetherwith many thoroughly practical advantages are successfully achieved. Asmany possible embodiments may be made of the above invention and as manychanges might be made in the embodiment above set forth, it is to beunderstood that all matter hereinbefore set forth or shown in theaccompanying drawings is to be interpreted as illustrative and not in alimiting sense.

I claim:

1. In a cam grinding machine having a base, a transversely movablerotatable grinding wheel thereon, a longitudinally movable table on saidbase, a rock bar on said table, a rotatable master cam spindle on saidrock bar, means to rotate said spindle, a work supporting center on saidspindle, a footstock having a work supporting center, means including amaster cam on said spindle and a follower roller on said table to rocksaid bar during a grinding operation to generate a predeterminedperipheral contour on the work piece, a work driving head rotatablysupported on said spindle, means including an adjustable cam mechanismto accelerate the rotation of said driver relative to said spindle, andmeans to adjust said cam mechanism so as to vary the angularacceleration of the work driver to generate a form of a predeterminedperipheral length on the periphery of a work piece being groundregardless of the diameter of the work piece.

2. In a. cam grinding machine having a base,

a transversely movable rotatable grindingl wheel thereon, alongitudinallymovable table on the-A base, a rock bar on said table. arotatable master cam spindle on said rock bar. means to rotate saidspindle. a work supporting center onsaid spindle. a footstock having aywork 'supporting center, means including a mastercam on said spindle anda follower roller on said table .toV lrock said bar duringa grindingoperation to generate a predetermined contour on-the work piecebeing'ground, a driving ange 'xedly mounted on said spindle,'a`workvdriver rotatably mounted on said spindle adjacent to said flange, andad- -d'riverxto facilitate grinding a form 6. In a cam-grindingmachine'havinga base.

a transversely movable. rotatable grinding wheel thereon.`aflongitudinally -rnovablet'ablaa rock baron` said table, varotatablefwork support on.

justable driving connections includingan adjust- 'able cam mechanisminterposed between -the flange and driver to accelerate the driverrelative to the Vmaster cam spindle so that-single master cam serves togenerate a form of a predetermined y peripheral length regardless ofthe` diameter'of the work piece.

3. In a cam grinding machine having a' base.

l a transversely movable rotatable grinding lwheel thereon, alongitudinally movable table onA the I base, a roel-: bar on saidtable,a rotatable mastercam spindle on said rock bar. means vtorotate saidspindle, av work supporting centeron said l spindle, a footstock havinga work' supporting I center, means including a master cainfon. saidspindle and a follower roller on said tableta rockl said bar duringagrinding operation to generate a predetermined contour on the workpiece being.` ground. a driving harige iixedlyv mounted on said saidrock g bar including a 'rotatablem'aster cam 1 vspindle havinga.;w'orksupportingfcenterj and va iootstock center, means to rotate saidmaster cam spindleVmeans including a master carnon said spindle 'andafollower rolleron vsaidtable'to roel; said bar vduring-a grindingloperation -,toge 1f1erate a predetermined contour on the roll to beground,

said Vmaster cam being shapedto generate a forml Y ofapredeterminedperipheral length on al fullsizejrolltofbe ground; a work driving headrotatably supported on said' spindle, means including an'adjustablecam-,mechanism to accelerate the rotation of. the driver relative to therotation ofthe 'spindle, and meansl to adjust said cam mechanisms() asto' vary the acceleration of the A tions.

spindlega work driver rotatably mounted on said spindle adjacent to saidilange. a radially movable slide on said flange. va non-radial groove'onsaid groove, and means including an adjustable cam mechanism 'to movesaid slide so as to accelerate the rotation of the driver relative tosaid ilange to facilitate grinding a Iorinof apredetermined.` peripherallength on tlieperiphery of the-work piece being ground regardless of thediameter of the work.

4.'In a camgrinding machine as claimed in claim 3, wherein the workdriver further includes a cam xedly mounted on' said rock bar, anadjustable bracketmounted on the periphery of;

said ilange, an arcuate shaped 'arm havingone end `p ivotally mol'u'itedon said bracket.` a rollerl on the other end of said arm engageablevwith vsaid cam, an elongated arcuate slot in said arm, and a stud onsaid slide which rides in said slot.; the adjustment of said bracketserving to .vary the extent of movement of said slide and thereby varythe extent of the accelerated movement-oi the driver relative to thespindle to facilitate grinding a form of. a predetermined Aperipherallength on the periphery of the work piecebeing around. f

5. In a camgrinding machine as claimed claim 3, in combination withtheparts and feadriver. a roller on said slide which rides in said ldriver'v relative to the rotation of the spindle to 1 vfacilitategrinding a form of the same peripheral length on the periphery of theroll vas itis reducedjin diameterv'by successive grinding operav -7. Inacamgrinding machine as claimed in claim r6,- in combination with theparts and fea#v tures therein s'peciiied vof-a 'work drive blockadjustably mounted'on saidwork driving head, and means to adjust saidblock vrelative to said. head toffacilitate positioning of the roll tobe ground relative tothe master cam. 1 .'8.'In al camgrinding machine asclaimed inv` claim 3, wherein the work driver further includes acamxedly mounted-on vsaid rock bar. an ad- 'justab'le bracket mounted onthe periphery of' .t said angeanharcuateshapedarm having one Ivend"pivtall'y mounted onsai'd bracket. aroller on the other end-ot said armengageable with said cam, anelongatedarcuate slot in said arm. and astud on said vslide which rides Tin said slot, the

adjustment of said bracketfserving `to vary the extent ofvmovefment 'orsaid slide and thereby-l vary the extent ofthe accelerated movement ofthe driven relative tov the A spindle to facilitate grinding aiorxn oalpredetermined peripheral. length on the `peripherynf the workpiecebeing `v ground. saidxcainon .the'rock-barbeing so shaped tures thereinspecified of an adjustable stop screw j on said ange engageable with astop surface on said driver. and a tensionvspring connected be'-l tweenthe ange and the driver normally to maintain said stop' surface inengagement-with lthe stop screw. said stop screw 'serving to limitv2.115,06:

ille of this'patent: i.'

Number Name v l Date" 1,879,506 Roberts -n." vsept.f.27; .19322,404,573A G laf 23;

